Method for operating a multi-nozzle extruder using zig-zag patterns that provide improved structural integrity

A method for operating a three-dimensional (3D) object manufacturing system comprising:

• selecting with a controller a first zig-zag pattern from a plurality of zig-zag patterns stored in a memory operatively connected to the controller;
• operating an actuator with the controller to move an extruder in an interior region in a first object layer, the movement of the extruder being relative to a platform supporting an object being manufactured to form swaths in the interior region in the first object layer using the first zig-zag pattern to move the extruder while extruding thermoplastic material through a plurality of nozzles in the extruder, the swaths of thermoplastic material formed in the interior region of the first object layer having straight portions and angled portions in the interior region in the first object layer, the straight portions being formed as the extruder is moved along a pair of orthogonal axes, one orthogonal axis being oriented at 0°-180° and the other orthogonal axis being oriented at 90°-270° and the angled portions being formed as the extruder is moved along paths other than one of the orthogonal axes;
• selecting a second zig-zag pattern from the plurality of zig-zag patterns stored in the memory;
• and
• operating the actuator with the controller to move the extruder in the interior region in a second object layer that is adjacent to the first object layer, the movement of the extruder being relative to the platform to form swaths in the interior region in the second object layer using the second zig-zag pattern to move the extruder while extruding thermoplastic material through the plurality of nozzles in the extruder, the swaths of thermoplastic material in the interior region of the second object layer having straight portions and angled portions in the interior region in the second object layer, all of the angled portions in the first object layer being oriented at either a positive or negative deviation from one of the orthogonal axes and all of the angled portions in the second object layer being oriented at the other of the positive or negative deviation from the same one of the orthogonal axes.